I am writing a fantasy/steampunk/horror novel, and I'm wondering if mixing different cultures is frowned upon. Specifically, my novel's setting is a mix of Italy, Ancient Rome, and Transalvania/Romania. The setting itself is based off of 19<sup>th</sup> century Italy, but the names, goverment structure, and empire resemble Ancient Rome. 

However, there are vampire-like creatures (who can also control the elements), and the other language occasionally spoken (mostly for nicknames and cursing) is Romanian. The creatures are also very diverse. There are for example: 

- sirens
- bean nighe's
- headlsss horsemen (they're kind of like ringwraiths)
- gods

Is mixing cultures okay, and if so, do you have any tips?